1. Field of the Invention
The present invention relates to a terminal connecting device which is connected to a radiotelephone unit system such as a mobile radiotelephone to make it possible to perform a data transfer.
2. Description of the Related Art
In recent years, there has been a proliferation of mobile radio communication systems such as portable and mobile radiotelephone systems.
In these systems, a data terminal such as a facsimile machine is connected to, for example, a mobile radiotelephone to be used as a mobile station device, thereby providing a data communication function in addition to a normal telephone communication function. Such a mobile radiotelephone system to which the data terminal is connected comprises a radio device, a telephone device, and a radio-telephone interface cable connecting the radio device to the telephone device.
In general, in the case where data is transferred to a data terminal connected to the mobile radiotelephone system from another subscriber's data terminal which is connected to a wire telephone network, the following data transfer procedure will be carried out.
Firstly, a subscriber desiring data transfer initiates "a call" to connect the mobile radio-telephone system to the wire telephone network. Then, a call-accepted signal is transmitted to the mobile radiotelephone system from the wire telephone network via the nearest radio station. As a result, in the mobile radiotelephone system, an alert signal is generated and the subscriber on the receiving side is informed.
If the subscriber on the receiving side carries out an "off-hook" by operation a predetermined key operation and responds to the off-hook, a response signal is sent from the mobile radiotelephone system to the wire telephone network via a radio line and a radio station. As a result, the data terminal on the transmitting side and the data terminal on the receiving side are connected to each other via a communication line by the wire telephone network. Under this condition, if the data terminal on the transmission side transmits a predetermined signal for data transfer to be performed, the signal is transferred to the mobile radiotelephone system on the receiving side and voice-outputted via the communication line. The subscriber, who has listened to the voice-output and confirmed the output, sets the terminal to be in a data transfer made by a predetermined key input operation of the mobile radio-telephone system. Thereafter, the operator pushes a predetermined receiving start key of the data terminal, and starts a receiving operation. Under this state, a response signal is transmitted from the data terminal on the transmission side from the data terminal on the receiving side to the data terminal on the transmission side. Thereafter, the data terminal on the transmission side starts the predetermined data transmission. In other words, in the conventional system, in order for the subscriber to receive data, the subscriber must push (i.e. input) a predetermined key, which is placed on a console unit provided in each of the mobile radiotelephone systems and the data terminal, a plurality of times by a manual operation.
In the conventional system, in order to reduce the above complicated manual operations, there has been considered an adapter having a dedicated circuit for performing an automatic receiving such as a tone ringer circuit inside. However, a complicated connection method and a connection cable or an interface must be made in accordance with the addition of such an adapter.
As mentioned above, every time the subscriber of the mobile radiotelephone system carries out data reception and transmission, the subscriber must set the mobile radiotelephone system and the data terminal to be in an operation mode, which can perform the data communication, by manual operation at least twice or more. Thus operation of the units is very complicated in performing the data communication. Particularly, if the subscriber is not in a car at the time of the data receiving, it is impossible to respond to the calling signal and data reception cannot be carried out. Moreover, in a case where the subscriber is driving the car, it is extremely difficult to perform the mode setting operation, and data reception cannot be carried out.
In order to connect an adapter having a dedicated circuit for performing an automatic receiving such as a tone ringer circuit inside, a power source dedicated to the adapter is needed in addition to the connection cord and the interface. As a result, there are problems locating mounting space for these additional devices and the wiring of the connection cord. On the other hand, incorporating the dedicated circuit for the automatic receiving in the mobile radiotelephone system enlarges the mobile radiotelephone system itself, and thus incur problems in the design of the mobile radiotelephone system and increase the manufacturing cost.
As mentioned above, there are many problems to be solved in the conventional system.
An object of the present invention is to provide a terminal connecting device, which is connected to a radiotelephone system without changing the basic specification of the radiotelephone unit such as a mobile radiotelephone system and its structure, and which can receive data by adding an automatic receiving function in which a subscriber does not have to carry out a mode setting operation in performing a data communication even if the subscriber is not in a car or is driving the car.
In order to attain the above object, the present invention provides the following two structures.
A terminal connecting device having a receiving transfer unit and a receiving response transfer unit is provided between a radiotelephone unit, which is connected to a communication network via a radio line and which has a predetermined receiving and transmitting control unit, and a data terminal device having a data receiving control unit for performing a data reception operation in accordance with a predetermined transfer procedure. Then, when a calling signal is supplied from the communication network to the radiotelephone unit, the incoming calling signal is detected by the receiving transfer unit of the terminal connecting device, and a receiving signal corresponding to the calling signal is generated. The receiving signal is transferred to the data terminal device and the data receiving control unit is started. Moreover, when a receiving response signal is generated by the data terminal after transferring the receiving signal by the receiving transfer unit, the receiving response signal is transferred to the radiotelephone unit by the receiving response transferring unit and thereby the receiving response signal is sent to the communication network by the receiving and transmitting control unit.
Moreover, a power supply unit using a power source of the radiotelephone unit is included in the terminal connecting device. Thereby, a power source output outputted from the radiotelephone unit is boosted, and a necessary predetermined power source voltage is generated in the data terminal device.
As a result of using the structure of the above-mentioned system, the following technical advantages can be obtained.
When the calling signal is sent from the telephone network via a radio line, the receiving signal is generated in accordance with the calling signal by the terminal connecting device, and transferred to the data terminal device. Due to this, in the data terminal device, a response control to the receiving signal is performed and a data receiving state is set. Moreover, when the predetermined receiving response signal is generated from the data terminal device, the receiving response signal is transferred to the radiotelephone unit via the terminal connecting device. Due to this, in the radiotelephone unit, the transfer line of the receiving data is switched and connected to the data terminal device and the communication line is established between the radiotelephone unit and the data terminal device on the receiving side. Therefore, the subscriber does not have to carry out the mode setting operations of the radiotelephone device and the data terminal device in receiving data. As a result, the data reception can be carried out even if the subscriber is not in a car or is driving the car.
Moreover, the power supply unit using the power source output outputted from the radiotelephone unit is provided in the terminal connecting device. Thereby, power for driving the data terminal device such as a facsimile machine mounted in the car can be easily ensured.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.